Space telephony.



L. DE PUREST.

SPACE TELEPHONY.

APPLICATION FILED JULY 8, 1907.

Patented Oct. 24, 1911.

T0 rek'om 'it may concern:

UNITED STATES PATENT OFFICE.

LEE nirormsr, or new YORK, N. Y., assmuoa r0 on roansr mmo summons 00.,a a coaroaarxou or new: roux.

'sracn 'riinnrnoii'r.

Be. it known that I, LEE on FOREST, a citia zen of the United States,and a resident of New York, in the county of New York and State of NewYork, have invented a new and useful Improvement in Space Telephony I,of which the following is a specification. I y invention relates tocertain novel 1mprovements and discoveries which I have made relating tothe art of transmitting signals between two separated points without theuse of artificial conductors and it' relates particularly to thewireless transmission of vocal or other sounds, including articulatespeech.

My invention comprises certain features, parts and combinations thereofwhich will be hereinafter described and particularly pointed out in theclaim.

The drawin s which accompany and form a part 0 this specificationrepresent in diagram several arrangements of apparatus and circuitswhich have been employed, although it will be understood that I do notlimit myself to the articular arrangements therein illustrate inasmuchas many modifications may be made in said apparatus and circuits withoutdeparting from the principle of my invention.

In the drawings, Figures 1, 2 and 3-represent space telephonetransmitting systems constructed in accordance with the presentinvention.

In the figures, G is a nerator of unidirectional electromotive orceherein rep resented as a direct current dynamo.

G is a polyphase generator, herein shown as a three-phase generator.

R R are resistances.

'C is a condenser. g

S is a discharger herein shown as a gap in which an electric arc may becreated between suitable electrodes;

S" is a discharger herein shown as a spark-gap.

S S are spark-gaps located in the transmitting antenna and herein shownin the earth connector thereof.

A is an antenna earthed at E.

M is a transformer of which the primary andlsecondary windings are I,and I respec: tive y.

T a transmitter herein shown as a microphone.

B is a battery.

. tor.

Specification or Letters l atent. Patented Oct. 24, 1911. Application maJuly 8, 1907. serial No. semen.

D Dare electromagnets.

signaling each signal element, as a dot or a dash, is transmitted by aseries of oscillations caused by a series of sin le sparks, the sparkseries representing di erent signal elements being separated by a periodof time in which there are no sparks. Each of thesesparks represents aseries of electrical oscillations of high frequency and of decreasingamplitude-that 18, the wave train sent out is damped and the rate ofdamping is greater or less depending on whether the oscillating systemat the transmitter is a good radiator or a good resona- For longdistance transmission it is desirable that the transmitting systemshould combine both qualitiesthat is, that it should have a very decidedperiod of itsown and should still radiate outwardly from its uprightwire a considerable amount of energy at every oscillation. In a stronglydamped wave train the first few oscillations, while of considerableamplitude, are soon sore'duced in amplitude as to be of little value inexciting a receiving antenna or [circuit into response. Such wave traintherefore has little cumulative excitin feet u on any receivingapparatus.

fore or the purpose of carrying out the .present lnvention I prefer touse an appav wave train, even if the maximum amplitude of the latter bemuch greater than that of the former. A receiving system whose naturalperiod of electrical vibration coincides with that of the wave trainwill ultimately pick up and respond to a weak but persistent wavetrain'by reason of the cumulative efi'ect of said wave train thereon.

In my resent invention I make use of a substantia ly contlnuou's seriesof waves, or as near an approach to a continuous radiation of waves asis practicable and modify which are herein described and illustrated inthe accompanying drawings.

potentials for radiatin It has been pointed outby Duddell, Peukert,Guthe, and Simon that if a circuit containing self-induction andcapacity be put in shunt around a direct current are and the resistanceof said are properly adjusted, the arc will give out a musica note, thepitch of which coincides with the frequency of the electricaloscillations in said shunt circuit. It has also been pointed out by ITesla that if said are be created in an atmosphere containing hydro en,the -operation thereof is mademore e cient. It is also known that if atelephone transmitter and battery be suitably associated with theaforesaid are and its circuit, words spoken in the microphonetransmitter will be reproduced and magnified in sound in the arcitself.In the case of a direct current are shunted by self-induction andcapacity and ordinarily poken of as the singing-arc, there is anternating or oscillating current in the shunt circuit which iscontinuously maintained b means of the direct current of the arc. Y T 'sis the exact electrical analogue ofthe acoustic henomenon wherea-continuous blast of air maintains a reed in rapid vibration, as in anorgan pipe. Where a microphone transmitter is associated with said areor its circuit, the minute current fluctuations produced in themicrophone circuit by the sonorous' vibrations of the air accompanyingthe sounds which afl'ect said microphone may be employed in various waysfor varying the amplitude of the cur.- rents in said are or its circuitin accordance with said sounds. We ma also employ s ark-balls for thepurpose 0 creati tlcally continuous trains of electrica oscillations,and in either case by using a source of direct current of suflicientlyhigh voltage and by reducing the dimensions of the selfinduction andcapacity in the shunt circuit, we may obtain for a proper length andresistance of ga the continuous generation of' electrical osci ations ofsuificiently high frequency to efiect the radiation of electromagneticwaves. Such an arrangement applied to wireless tel phy is shown in Figs.1 and 2 in which e circuits S 0 I are sources of undam ed or practicallycontinuous elec- .trical osc1 lations of high frequency. Theoscillations in these circuits may be transmitted to the radiatingantenna A in any suitable manner and asjshown herein the oscillationtransformer M is employed for this purpose. By this arrangement theotential of the direct current source G need he only moderate becausethe desired high purposes may be obtained by said trans ormer in whichthe ratio of transformation may be as large as desired. The directcurrent potentials are in no case measures of the potentials ex'istingin the oscillation circuit since by the resonance eifects of the latter,a large increase in. electromotive force always 1s obtained. Wherehowever it is desirable to obtain direct current potentials in excess ofthose conveniently obtainable from a direct current generator, thearrangement shown in Fig. 3 may be employed.

' n Fig. 3, the conductors of the threephase generator G are connectedto the points 1, 2, 3, which may be inclosed in a suitable vessel 5, andto the star-point 0 of zero potential through the inductances L L Lrespectively. If from said starpoint a conductor be led to the plate 4,there will be obtained in said conductor a unidirectional currentflowing in the direction of the arrow, said current being the resultantof the currents flowing through the vessel 5, which may contain anysultable atmosphere maintained at any desired ressure, from the pointsto the plate. Th1s resultant unidirectional current will be practicallya constant current and of a volta practically equal to that of thealternating currents delivered by the generator G. As will be obvious atransformer may be interposed between the point-and-plate arrangementwhich constitutes a polyphase rectifier, an the generator G. 'I' do notlimit myself to the particular form of lyphase rectifier shown in Fig.3inasmuc as various other forms may be employed for securing from a highpotential polyphase current a unidirectional currento any desiredvoltage. In the circuit which includes the point 0 and plate 4 adischarger S for the condenser C may be inserted and there will be.polyphase system may be connected hearth and the antenna A may beassociated in any, suitable manner with the oscillation circuit,

the associating means being shown in the present instance as consistingofthe autotransformer M.

If a continuous wave train produced by the transmitting systems shown inFigs. 1, 2 or 3 impinges upon a receiving antenna and if the amplitudesof said wave trains are varied in any arbitrary manner and at any ratewithin the limit of audibility or within the limit of response of thediaphragm of a telephone receiver, which is properly associated with anoscillation detector, sounds of corresponding intensities producecorresponding changes and rates of vibration will be produced by saidtelephone reeciver. It is therefore only necessar to alter theamplitudes of the waves 0 the continuous train of waves produced at thetransmitting station to correspond with the amplitudes and rates ofvibration of the acoustic waves to be trans: mitted, to bring aboutreproductions of such acoustic vibrations in the receiver, be theseCurrent fluctuations produced in the cir cuit of the battery B andtransmitter T in the strength of the magnetic field across the gap andsuch changes in strength of said magnetic field produce correspondingvariw tions in the amplitude of the electrical oscillations created inthe circuits of the ga s S or S. As shown in Fig. 1, the transmlttingcircuit with its magnets D D, may be associated with the source ofpractically continuous electrical oscillations, while as shown in Figs.2 and 3, it may be associated with a gap S included in the antennacircuit, preferably in the earth connector thereof where the current isa maximum and where it serves as a resistance, without, however,interruptin the continuity of the oscillations surging ack and forththerethrough, the conductivity of such resistance being varied byvarying the strength of the magnetic field in which it is placed.

It will be noted that the electrical waves which 'are depended upon forthe transmission from one station to another are not the impulses whichare directly produced bythe action of the sound waves or the currents inthe circuit of the microphone. transmitter, but are waves which areproduced in a circuit which is distinct from such microphone circuit andare not dependent for their production or primary intensity upon theaction of said microphone. any necessary relationship between the periodor the transmitting-impulses and the period of the sound waves. Theperiods of the sound waves correspond with the periods of the variationsin intensity of the transmitted electroma etic waves. In other words,the rate of vlbration of the transmitted waves is wholly distinct fromthat of the sounds to be transmitted and the amplitude of said waves isvaried in accordance with that of said sounds, and the rate of variationof the amplitude of said waves corresponds with the rate of vibration ofsaid sounds.

I claim:

In a space tele" hone transmitting system, a transmitting antenna, meansfor developing electrical oscillations therein, spark-electrodes in saidantenna, electro-magnets arranged in proximity thereto and a telephone.transmitter and source of electrical energy associated withsaidelectromagnets.

In testimony whhreof, I have hereunto subscribed my name this 3d day ofJuly, 1907.

1 LEE on FOREST. Witnesses:

Rosoon KENT, Tnoms I. GALLAGHER.

Neither is there i

